TELECOMMUNICATIONS SITES

Related Application

[0001] The present application claims priority from and the benefit of U.S. Provisional Patent Application No. 63/320,323, filed March 16, 2022, the disclosure of which is hereby incorporated herein by reference in full.

Field of the Invention

[0002] The present invention relates generally to telecommunication sites, and more particularly to providing power to telecommunication sites.

Background

[0003] In many information and communication technology systems, network-connected electronic devices are deployed in locations where a local electric power source is not available. With the proliferation of the Internet of Things ("loT"), autonomous driving, fifth generation ("5G") cellular service and the like, it is anticipated that network-connected electronic devices will be deployed at locations that lack a conventional electric power source with increasing frequency.

[0004] There are a number of ways to provide electric power to such remote network- connected electronic devices. For example, the local electric utility company can install a connection to the electric power grid. This approach, however, is typically both expensive and time-consuming, and unsuitable for many applications. Composite power-data cables can also be used to power remote network-connected electronic devices and provide data connectivity thereto over a single cabling connection. Composite power-data cables refer to cables that can transmit both electrical power and data. Power-over Ethernet ("PoE") cables are one type of composite power-data cable. However, PoE technology has limitations in terms of both data communication throughput and the amount of power delivered, and these limitations become more restrictive the greater the distance between the remote network-connected electronic device and the PoE source. For example, under current PoE standards, high throughput data communications is only supported for cable lengths of up to about 100 meters, and even at these short distances the power delivery capacity is only about 100 Watts. Power-plus fiber cables are another example of a type of composite power-data cable that includes both power conductors and optical fibers within a common cable jacket. Power-plus-fiber cables, however, can be prohibitively expensive to install for many applications. Other known types of composite powerdata cables include coaxial cables, telephone twisted pair cables with remote power feeding on some pairs and direct subscriber line (DSL) data on other pairs or with both power and DSL on the same pairs, and composite cables having larger conductors (e.g., 10-12 AWG) for power transmission and smaller gauge twisted pairs for data transmission.

[0005] In many telecommunications applications, a power interface between the power source and the site is included. Typically power supplied by the power source is at a high voltage in order to reduce power loss, then is transformed/converted to a lower voltage near the site. Lower voltage power provides greater safety and ease of installation and maintenance (for example, low voltage can reduce any hazard of electric shock and lower power can reduce any fire hazard), and thus is desirable at the site itself. Moreover, the voltage often must be reduced at the site to suitable values for powering the equipment at the site. However, the lower voltage power is typically delivered over relatively short distances to reduce power loss. One common power interface used to downconvert the power signal from high voltage to low voltage in such sites is the NEC Class 2 interface. Class 2 circuits are defined in the National Electrical Code NFP 70, Article 725, and the performance requirements for Class 2 transformers are defined in UL 5085-1 and U1 5805-3, and CSA C22.2 Nos. 66.1 and 66.3. Generally speaking, Class 2 transformers are non-rectifying, have a 600 V DC maximum primary input, a 60 V DC maximum primary output, and are limited to 100 VA on the supply side. They also are often double insulated or have reinforced insultation, which can eliminate the need for a protective grounding connection.

[0006] In many instances, such sites are also fed by fiber optic cable that carries data, and in many instances a composite fiber/power cable may be used to transport both power and data. One exemplary system is Power Shift Metro System offered by CommScope, Inc. (Hickory, North Carolina), which is designed to feed power and data to small cell base stations. More detail is offered in U.S. Patent Publication No. 2020/0027629 to Craft, the disclosure of which is hereby incorporated herein by reference in full. The typical Power Shift installation includes a separate enclosure fed by the composite fiber/power cable in which the power carriers are separated, or “broken out” from the data-carrying fiber optic cables. The power carriers are then fed to an interface (such as one that includes a transformer conforming to the NEC Class requirements discussed above) for transforming into lower voltage power for the site.

Summary

[0007] As a first aspect, embodiments of the invention are directed to a closure for a telecommunications network. The closure comprises: a housing having an internal cavity; first fiber and power connectors mounted on the housing; second fiber and power connectors mounted on the housing; a fiber optic module mounted in the cavity, the fiber optic module configured to receive signals from a first number of optical fibers, output signals from the first number of fibers to the first fiber connector, and output signals from a second number of fibers to the second fiber connector; and a DC/DC converter mounted in the cavity, the DC/DC converter configured to receive power at a first voltage, output power at the first voltage to the first power connector, and output power at a second voltage that is lower than the first voltage to the second power connector.

[0008] As a second aspect, embodiments of the invention are directed to a closure for a telecommunications network comprising: a housing having an internal cavity; first fiber and power connectors mounted on the housing; second fiber and power connectors mounted on the housing; a fiber optic module mounted in the cavity, the fiber optic module configured to receive signals from a first number of optical fibers, output signals from the first number of fibers to the first fiber connector, and output signals from a second number of fibers to the second fiber connector; and a DC/DC converter mounted in the cavity, the DC/DC converter configured to receive power at a first voltage, output power at the first voltage to the first power connector, and output power at a second voltage that is lower than the first voltage to the second power connector. The closure is buried underground.

[0009] As a third aspect, embodiments of the invention are directed to a closure for a telecommunications network comprising: a housing having an internal cavity; first fiber and power connectors mounted on the housing; second fiber and power connectors mounted on the housing; a fiber optic module mounted in the cavity, the fiber optic module configured to receive signals from a first number of optical fibers, output signals from the first number of fibers to the first fiber connector, and output signals from a second number of fibers that is lower than the first number of fibers to the second fiber connector; and a DC/DC converter mounted in the cavity, the DC/DC converter configured to receive power at a first voltage, output power at the first voltage to the first power connector, and output power at a second voltage that is lower than the first voltage to the second power connector. The DC/DC converter is configured to provide power at the second voltage that meets NEC Class 2 specifications.

Brief Description of the Figures

[00010] FIG. l is a schematic diagram of an exemplary small cell base station network.

[00011] FIG. 2 is a schematic diagram of a small cell base station of the network of FIG.

1.

[00012] FIG. 2A is a schematic diagram of a small cell base station antenna of the network of FIG. 1 showing an arrangement with three radios.

[00013] FIG. 3 is a schematic diagram of a small cell base station according to embodiments of the invention.

[00014] FIG 4 is a schematic diagram of a composite closure used with the small cell base station of FIG. 3, with a transformer shown in inset.

[00015] FIG. 5A is a schematic diagram of a WDM optical fiber module that can be used with the small cell base station of FIG 3.

[00016] FIG. 5B is a schematic diagram of a splitter fiber optic module that can be used with the small cell base station of FIG 3. [00017] FIG. 6A is a schematic diagram of a series of DC/DC converters that may be used in the closure of FIG. 4.

[00018] FIG. 6B is a schematic diagram of a multi-output DC/DC converter that may be used in the closure of FIG. 4.

[00019] FIG. 7A is a schematic cable diagram for a small cell base station with a single radio.

[00020] FIG. 7B is a schematic cable diagram for a small cell base station with three radios.

Detailed Description

[00021] The present disclosure will be described below with reference to the attached drawings, wherein the attached drawings illustrate certain embodiments of the present disclosure. However, it should be understood that the present disclosure may be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the disclosure of the present disclosure more complete and to fully explain the protection scope of the present disclosure to those skilled in the art. It should also be understood that the embodiments disclosed in the present disclosure may be combined in various ways so as to provide more additional embodiments.

[00022] It should be understood that in all the attached drawings, the same symbols denote the same elements. In the attached drawings, the dimensions of certain features can be changed for clarity.

[00023] It should be understood that the words in the Specification are only used to describe specific embodiments and are not intended to limit the present disclosure. Unless otherwise defined, all terms (including technical terms and scientific terms) used in the Specification have the meanings commonly understood by those of ordinary skill in the art. For brevity and/or clarity, well-known functions or structures may not be further described in detail. [00024] The singular forms “a”, “an”, “the” and “this” used in the Specification all include plural forms unless clearly indicated. The words “comprise”, “contain” and “have” used in the Specification indicate the presence of the claimed features, but do not exclude the presence of one or more other features. The word “and/or” used in the Specification includes any or all combinations of one or a plurality of the related listed items. The words “between X and Y” and “between approximate X and Y” used in the Specification shall be interpreted as including X and Y. The words “between approximate X and Y” and “from approximate X to Y” used in the Specification means “between approximate X and approximate Y” and “from approximate X to approximate Y”, respectively.

[00025] In the Specification, when it is described that an element is “on” another element, “attached” to another element, “connected” to another element, “coupled” to another element, or “in contact with” another element, etc., the element may be directly on another element, attached to another element, connected to another element, coupled to another element, or in contact with another element, or an intermediate element may be present. In contrast, if an element is described “directly” “on” another element, “directly attached” to another element, “directly connected” to another element, “directly coupled” to another element or “directly contacting” another element, there will be no intermediate elements. In the Specification, a feature that is arranged “adjacent” to another feature, may denote that a feature has a part that overlaps an adjacent feature or a part located above or below the adjacent feature.

[00026] In the specification, words expressing spatial relations such as “upper”, “lower”, “left”, “right”, “front”, “rear”, “top”, and “bottom” may describe the relation between one feature and another feature in the attached drawings. It should be understood that, in addition to the locations shown in the attached drawings, the words expressing spatial relations further include different locations of a device in use or operation. For example, when a device in the attached drawings rotates reversely, the features originally described as being “below” other features now can be described as being “above” the other features. The device may also be oriented by other means (rotated by 90 degrees or at other locations), and at this time, a relative spatial relation will be explained accordingly.

[00027] Referring now to FIG 1, a small cell base station network, designated broadly at 100, is shown therein. The network 100 includes a rectifier/power supply 102 that is connected to power supplied by a local utility. The rectifier/power supply 102 is mounted above ground level (AGL in FIG. 1), and is typically employed to convert AC power to relatively high voltage (e.g., 380V) DC power for use in the network 100. A plurality of small cell base stations 104 (illustrated in FIG. 1 as four small cell base stations 104) are deployed above ground. These typically include one or more antennas, one or more radios connected with the antennas, and other signal processing and power distribution equipment.

[00028] A composite closure 106 is buried below ground level (BGL in FIG. 1) and is electrically connected with the rectifier/power station 102 via power branches 108. The composite closure 106 serves as a termination/interface point for power conductors and as a splicing/interconnection point for fiber optic cables. An exemplary composite closure 106 is the FOSC-450, available from CommScope, Inc. (Hickory, North Carolina).

[00029] A fiber optic splice closure (FOSC) 109 is buried below ground and receives fiber optic signals via a buried fiber feeder 110. An exemplary FOSC 109 is the FOSC-450, available from CommScope, Inc. (Hickory, North Carolina). A branch fiber optic cable 113 optically connects the FOSC 109 with the composite closure 106.

[00030] The composite closure 106 is connected for power and data via power/fiber cables 116 with a plurality of below-ground composite closures 112, wherein each composite closure 112 is associated with a respective small cell base station 104. The composite closures 112 may be of the same construction as the composite closure 106 and/or the fiber optic closure 109. It can be seen in FIG. 1 that the network 100 is arranged such that two power/fiber cables 116 connect directly with the composite closure 106, with each power/fiber cable 116 connecting at its opposite end directly with a respective composite closure 112. Additional power/fiber cables 116 are routed between adjacent composite closures 112, which are therefore connected cognately with the composite closure 106. Exemplary power/fiber cables 116 may include 4 12AWG wires and up to 144 optical fibers. In some embodiments the power/fiber cables 116 may be separate (i.e., non-hybrid) power and fiber cables.

[00031] As shown in FIGS. 1 and 2, a power cable 120 and a fiber cable 122 are routed from each composite closure 112 to its respective small call base station 102. The fiber cable 122 is routed to a fiber interface 124; another fiber cable 126 is then routed from the fiber interface 124 to a radio 130 mounted near the top of a pole 132 of the small cell base station 102. [00032] The power cable 120 is routed to a power node 134. The power node 134 is configured to provide a transformation site for higher voltage power entering the power node 134 (e.g., -190V/+190V, or a magnitude of 380V) to lower voltage power exiting the power node 134 (e.g., 3 x 48V, which is typical for NEC Class 2 interfaces). Lower voltage power cables 136 are routed from the power node 134 to the radio 130 and provide a lower voltage power (e.g., 48V) that is appropriate for the radio 130 and/or other equipment of the small cell base station 104. Because the lower voltage power cables 136 are routed only a relatively short distance, the cable voltage drop is relatively insignificant; consequently, the transformation to NEC Class 2 or other reduced power protocol at the power node 134 does not significantly affect performance of the radio 130 or other equipment.

[00033] An alternative arrangement is shown in FIG. 2 A, wherein three radios 130 are mounted at the top of the pole 132; three power cables 136 are routed from the power node 134 to respective radios 130, and three fiber optic cables 126 are routed from the fiber interface 124 to respective radios 130.

[00034] It has been recognized that, under some circumstances, the power requirements of a small cell base station are relatively low. Exemplary circumstances under which reduced power needs are present may include distributed antenna system (DAS) base stations and WiFi access points. Other remote electronic equipment, such as remote cameras or sensors, may also have low power requirements. In such instances, a longer span of lower voltage power cable may be employed, as the higher cable voltage drop that accompanies the increased cable length does not prevent sufficient voltage from reaching the attached radio or other equipment. As an example, DAS radios typically have a shorter transmission range, and therefore require less power for adequate transmission.

[00035] One potential benefit flowing from the lower power requirements may be the ability to reduce the amount of equipment (i.e., the number of devices deployed) that are employed for an installation. Referring now to FIG. 3, a small cell base station 202 illustrated therein includes many of the components of the small cell base stations 102 of the network 100, but does not have a power node such as that shown at 134 in FIG. 2. Instead, a network 200 of small cell base stations 202 employs one or more modified composite closures 206, 212 associated with each of the sites that includes therein a DC/DC converter 230 (see FIG. 4) to reduce or “step down” the voltage of the power signal within the composite closure 212 that is fed to an adjacent small cell base station 202, while enabling the “pass-through” of higher voltage power to connected composite closures 212. [00036] An exemplary composite closure 212, which is fed by a composite fiber/power cable 216, is shown schematically in FIG. 4. The composite closure 212 includes a housing 240, an internal fiber module 242 of known configuration, and the aforementioned DC/DC converter 230. The fiber module 242 and the DC/DC converter 230 are mounted within a cavity 246 of the housing 240. A fiber/power cable 216 is routed to the housing 240. Fibers from the composite cable 216 are optically connected with the fiber module 242. Power conductors from the composite cable 216 are routed to and electrically connect with the DC/DC converter 230.

[00037] A set of fiber and power connectors 252, 254 are mounted on the housing 240 (these may be replaced by a single hybrid power/fiber connector). The fiber connector 252 is optically connected with the fiber module 242. Typically, the fiber connector 252 is configured to transmit signals from a lower number of fibers than are present in the fiber/power cable 216 (e.g., there may be 12 optical fibers in the fiber/power cable 216, but only one or two fibers may be connected with the fiber connector 252). Thus, the fiber module 242 serves to allow the fiber connector 252 to “tap into” the fiber/power cable 216 and receive only selected signals therefrom.

[00038] The power connector 254 is connected with the DC/DC converter 230. Importantly, the power exiting the composite closure 212 through the power connector 254 is “stepped down” by the DC/DC converter 230 to a lower voltage (e.g., -48V) than that entering the composite closure 212 via the fiber/power cable 216 (which may be, for example, - 110V). The power cable 258 may then be routed directly to the radio 204 rather than requiring a separate power node like that shown in FIGS. 1 and 2. Thus, the DC/DC converter 230 enables the power connector 254 to tap into the fiber/power cable 216, but does so to provide a lower voltage to the power connector 254.

[00039] The fiber and power connectors 252, 254 are sized to connect with a fiber/power cable 256 that is routed to the radio 204 or other device of interest. In some embodiments, the fiber/power cable 256 may be provided as two separate cables (one of which carries power, and the other of which provides optical signals).

[00040] In addition, the composite closure 212 includes a set of fiber and power connectors 262, 264 mounted on the housing 240. The fiber connector 262 is optically connected with the fiber module 242, and the power connector 264 is connected with the transformer 230. Again, in some embodiments the fiber connector 262 and the power connector 264 may be configured as a single hybrid connector. A fiber/power cable 266 is connected with the fiber and power connectors 262, 264. The power exiting the composite closure 212 through the power connector 262 “passes through” the composite closure 212 at substantially the same voltage as that entering the composite closure 212 via the fiber/power cable 216. Similarly, the fiber connector 264 is configured to transmit signals from the same number of fibers as the fiber/power cable 216; as such, optical signals “pass through” the closure 212. The fiber/power cable 266 is routed to another composite closure 212 in the manner illustrated in FIG. 1 for composite closures 106, 112.

[00041] FIGS. 5A and 5B illustrate two different types of fiber modules 242. FIG. 5A shows a wavelength-division multiplexing (WDM) module 242, and FIG> 5B shows a splitter module 242’. Either of these types may be suitable for use in the composite closure 212.

[00042] FIGS. 6A and 6B illustrate two different types of DC/DC converters 230 that may be particularly suitable for use with small cell base stations 202 that have three antennas 204.

FIG. 6A shows a series of three converter units 231, each of which provide reduced voltage (e.g., 48V) output to power cables 256. FIG. 6B illustrates a multi-output DC/DC converter 230’ that comprises a single unit.

[00043] The DC/DC converter 230 may be any DC/DC converter known to reduce an input voltage to a lower desired output voltage. In some embodiments, the DC/DC converter 230 may be a non-hardened plug-in DC/DC converter, and/or may be replaceable. In some embodiments, the DC/DC converter 230 may be configured to meet the specifications of an NEC Class 2 converter as defined in UL 5085-1 and U1 5805-3. Also, in some embodiments the DC/DC converter 230 may be configured for removal without interruption of operations of the remainder of the network 200.

[00044] FIGS. 7A and 7B schematically illustrate the routing of composite cable 256 from the composite closure 212 to the radio 230. FIG. 7A illustrates the routing of a cable 256 (with two power conductors and two optical fibers) from the connectors 252, 254 on the composite closure 212 to a single radio 230. FIG. 7B illustrates the routing of a cable 256’ (with N x 2 power conductors and N x 2 optical fibers) from the connectors 252, 254 to N radios 230’. [00045] It can be envisioned that the employment of one or more composite closures 212 within the network 200 can be beneficial for multiple reasons. First, the use of the composite closure 212 may eliminate the need for a power node and/or a fiber optic interface for each individual small cell base station 212, which can save costs on both equipment and labor. Second, because the fiber/power cable 256 routed from the composite closure 212 carries only lower voltage power, a lower cost cable may be employed over a longer distance. (This may be the case whether power is provided as a separate cable or as part of a composite cable). Typically for a DAS small cell network, the fiber/power cable 256 may be able to be routed from 100 to 1,000 feet between the composite closure 212 and the radio 204 and still provide adequate power.

[00046] It may also be understood that, as desired for the site, the composite closure 212 may be positioned below ground or above ground. If positioned above ground, the composite closure 212 may be mounted on the pole, near the radios, or at any convenient position therebetween. It can also be seen from FIG. 2A that if the composite closure 212 is mounted above ground, the composite cable 216 that exits the composite closure 212 and is routed to the next small cell base station may be above ground also.

[00047] Those of skill in this art will appreciate that the components discussed above may take different forms. As one example, power and fiber cables that are discussed herein as separate cables that are routed along the same path may be employed as hybrid cables, and vice versa. Similarly, power and fiber connectors that are described herein as separate may be combined as hybrid fiber/power connectors. A power node such at that shown at 134 in FIGS. 1 and 2 may be included in the base stations 202 of the network 200 to ease connectivity. The fiber interface may be omitted in some embodiments. Other variations will be apparent to those of skill in this art.

[00048] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as recited in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.